INVESTIGATING THE EFFECTS OF SHEA NUT PROCESSING CONDITIONS ON THE YIELD AND QUALITY OF TRADITIONALLY PRODUCED SHEA BUTTER

Abstract

Agricultural diversification has been identified as part of measures for minimising global yearning for developing opportunities for sustainable production systems. Processing of Shea nut into Shea butter is mostly carried out by women in Nigeria using traditional methods. This approach is currently not well-standardized and has significant impact on the yield and product quality. Robust investigations of process variables are needed to identify the most important process parameter(s) that would guarantee high yield and good quality Shea butter. In this study, effects of Shea kernel roasting temperature (30, 90 and 150 oC), roasting time (10, 35 and 60 minutes), Shea paste kneading speed (100, 200 and 300 rpm), and time lag between Shea kernel milling and Shea paste kneading (5,15 and 25 minutes) on the yield and quality of Shea butter produced through traditional extraction method were evaluated. At 30 oC roasting temperature, 31.68 wt % Shea butter was recorded, which increased to 36.4 wt % when the roasting temperature was raised to 150 oC. Free fatty acid content increased significantly from 1.28 to 2.1 % while the peroxide value was maximum at 100 oC (2.1 meq/kg). Longer roasting time and time lag between milling and kneading also led to high free fatty acid and peroxide contents. This study indicates that the roasting temperature, roasting time and time lag between milling and kneading represent the most significant parameters for high yield and good quality Shea butter production via traditional extraction method. Keywords: Shea kernel; free fatty acid; kneading speed; Shea butter quality.